Doc Rivers is going to be rewarded for guiding the Boston Celtics to their first NBA championship in 22 years.

According to a report on Yahoo.com Tuesday night, Rivers has agreed to a two-year contract extension that will run through the 2010-11 season. He had been under contract through the upcoming 2008-09 season.

Rivers, who turns 47 next month, finished second in the NBA coach of the year voting behind Byron Scott of the New Orleans Hornets after the Celtics went 66-16 in the regular season.

Armed with newcomers Kevin Garnett and Ray Allen, Rivers presided over the best single-season turnaround in NBA history as the Celtics improved from 24-58 in 2006-07.

The Celtics defeated the Los Angeles Lakers in six games in the NBA Finals to win their first title since 1986.

According to the report, Rivers will be paid $5.5 million annually with postseason incentives that could increase his salary to $7 million.

Yahoo.com reported that Rivers’ agent, Lonnie Cooper, is wrapping up the final details and that Rivers said in a text message he didn’t want to make “a big deal about” the extension.

Rivers signed a four-year, $20 million deal when he joined the Celtics in 2004 and received a one-year extension in May 2007. Rivers did not want to enter the 2007-08 season as a lame-duck coach, and the team’s management agreed to his request.

After signing that extension, Rivers’ roster was upgraded significantly when Allen was acquired from the Seattle SuperSonics and Garnett was brought in from the Minnesota Timberwolves.

Those two All-Stars joined Paul Pierce to form the nucleus of a team that dominated the regular season. After struggling to get past the Atlanta Hawks and Cleveland Cavaliers in the first two rounds, the Celtics eliminated the Detroit Pistons in six games and took care of the Lakers.

Rivers is 168-160 in four seasons with the Celtics and a combined 339-328, including his stint as coach of the Orlando Magic.

After being fired by Orlando early in the 2003-04 season, Rivers went to work for ABC-TV as an analyst and was then hired by the Celtics.

In his first season in Boston, Rivers led the Celtics to the Atlantic Division title with a 45-37 record, but they were shocked by the Indiana Pacers in seven games in the opening round, losing the deciding game by 27 points at home.

The Celtics were in a rebuilding phase the next two seasons, going 33-49 in 2005-06 and finishing with the second-worst record in the league the following year. Pierce was sidelined for nearly half of the season with injuries, and the Celtics were shorthanded for much of the year.

There was speculation as to whether Rivers would be back in the ’07-08 season, but the Celtics gave him a vote of confidence with the one-year extension less than a month after the dreadful ’06-07 season ended.